The Postmortem Pathology Section, along with the Cytopathology Section, Hematopathology Section, Surgical Pathology Section, and Ultrastructural Pathology Section, provide a complete service in Anatomic Pathology for the Clinical Center as well as other institute patients. In addition, when the use and study of human pathological material is requested by research staff of any of the institutes, the Postmortem Section makes every effort to collaborate with and/or supply the researchers with the human tissues upon approved request. The autopsy material is utilized by staff and residents for research projects involving clinicopathological correlation and characterization of disease processes. Currently, several projects are on-going: immunohistochemical staining of various tissues with protease and nonmuscle myosin antibodies; wide organ sampling from all AIDS cases with PCR, immunohistochemical and histological analysis of HIV; clinicopathologic correlation in dementias; neuroimaging correlation in demyelinating disease; histologic correlation of in vitro NMR characterization of normal brain; and in situ hybridization for HSV in a patient with zoster myelitis/encephalopathy. Additionally, a database of major autopsy diagnoses from 1982 through 1990 is being compiled, with pertinent historical information included.